This interdisciplinary research program in immunodermatology will incorporate both clinical and basic scientific studies to investigate skin diseases which are caused by abnormalities of immunologic function. Immunologic (cellular and humoral), biochemical, ultrastructural, and cell culture techniques will be employed to investigate the pathogenesis of allergic contact dermatitis, lichenoid skin diseases, cutaneous vasculitis, lupus erythematosus, blistering diseases, scleroderma, dermatomyositis, and mast cell mediated skin diseases. Seven investigators will pursue five areas of research: (1) The role of the epidermal Langerhans cell in allergic contact sensitivity and the mechanism of experimentally induced specific unresponsiveness to contact allergens. (2) Mechanisms of immunologic injury in leukocytoclastic and lymphocytic vasculitis. (3) The role of dermal connective tissue in localizing or sequestering antigen and/or antigen-antibody complexes. (4) The role of cellular immune injury in the pathogenesis of chronic inflammatory skin disease. (5) The role of mast cells in cutaneous inflammation and pharmacologic modulation of mast cell mediated inflammation. These studies will provide a clearer understanding of the basic mechanisms involved in the pathogenesis of several common, incapacitating cutaneous diseases.